Distribution of polishing times for a wafer with different patterned polishing pads during CMP and CCMP

During chemical-mechanical polishing (CMP), the polishing pad is placed under a wafer and it completely covers the wafer. Compensating CMP (CCMP) decreases the polishing pad wear and enhances end-point detection (EDP). In CCMP, a polishing pad is placed above the wafer and does not completely cover the wafer. Regardless of CMP or CCMP, there are grooved patterns on the polishing pads. However, on the difference in polishing situations as affected by the polishing pads with different grooved patterns during polishing of wafer, theoretically there was no past reference with related studies. This study analyzes the effects of various pattern designs–concentric circles, grids, spirals and waves–on polishing pads. A numerical analytical model constructed in this study is utilized to analyze and compare the distribution of polishing times, also the polishing pads with different patterns during CMP or CCMP analytic results can function as a qualitative reference for the planarization of processing and a reference for selecting an appropriate pattern design for polishing pads. The analytic method adopts CAD-designed patterns and shapes, which are converted into a binary matrix by image processing. The various profiles and patterns of polishing pads, as well as different polishing paths, are also considered. Problems such as deformation caused by turning the pattern, ineffective polishing and the transformation of shape pixels to a physical length are corrected.